Effect of the Addition of Oxidizing Agents on the Synthesis of 8-Chloro-2-methylquinoline by the Doebner-Miller Method

Abstract

Effect of the addition of oxidizing agents, such as nitrobenzene, o-chloronitrobenzene, mdinitrobenzene, acetaldehyde, SnCl₄ and I, on the yield of 8-chloro-2-methylquinoline in the Doebner-Miller reaction between crotonaldehyde or paraldehyde and o-chloroaniline in the presence of 30% aqueous HCl was studied.
The addition of nitrobenzene or o -chloronitrobenzene increased the yield, whereas the other oxidizing agents did not. Nitrobenzene did not increase the yield of 8-nitro-2-methylquinoline in the reaction of o-nitroaniline and crotonaldehyde. Further quantitative studies were made on the Doebner-Miller reaction for the synthesis of 8-chloro-2-methylquinoline from crotonaldehyde or paraldehyde and o-chloroaniline in the presence of nitrobenzene or o-chloronitrobenzene.